Resistance element.



0 6 m 8 4 CROSS REFERENQE EXAMINER E. SCHWARTZ.

RESISTANCE ELEMENT. APPLICATION min :uns ls. 191e4 1,281,218. .Patented 0ct..8,191s.

/of-M or rough' handling which utensils of this residin /ZaO/Z lf UNITED sTATEs `PATENT oEFIcE.

SCHWARTZ, A0F NEW YORK, N. Y., ASSIGNOR T0 MANHATTAN VELEGTBICLAII: SUPPLY COMPANY, INC., 0F JERSEY C ITY, NEWJERSEY, A CORPORATION 0F MASSA- To all whom it may 'concern Be it known -that I, EDWARD SCHWARTZ, a citizen of the United Statesof America, in the-city, county, and State of New ork, have invented certain new and useful Improvements in Resistance Elertrients, of ,which the following is a specifica- My inventionl relates to resistance olements and particularly to resistance elements adapted to be used in such toilet utensils as.

hair curlers, drying combs, etc., in which a compact heatin unit 'of moderate capacity is required an the object of my invention is to provi e an 'element of this type which can be manufactured rapidly and inexpen sively, while, at the same time, affording, 1n the finished product, an eiiicient unit capable of giving satisfactory service and of such durability of construction that it can with stand, without danger of injury, the careless type are apt to receive.

n the accompanying drawing,

Figure 1 is a broken side elevation illustrating a resistance clement embodying my invention in one form;

Fig. 2 is a side elevation of a section ycut from a len h of the resistance element and folded to s ape;

Fig. 3 is a side elevation of a completed unit showing the holding ferrules applied thereto;

3 Fig. 4 is a seccin en the lia@ 4 4, Fig.

and "Figpis a broken side elevation showing -a modified construction.

In the form illustrated in Figs. 1 to 4, the present .heating unit comprises a -soft core 10 of insulating material such as strands of asbestos liber, upon which is spirally wound the resistance wire 11. By -reason of the fact' that the insulating core 10 is of yielding material and the vwire 11 is wound thereon under slight tension, the coill is slightl pressed into the surface 4of the core, whi

'thus has the mechanical efectof spacing the sEires of .the coil apart and prevent' the s ort-circuit thereof. For utensils o the present type, it is suilicent to use a wire of such s1ze and lcharacter that it aords a resistance of 400 to 600 ohms per foot. Outside'the resistance coil is wound, under sli ht tension, strands 12 of insulating matenal,

specmcauon of man raten.

Application illed Jnne 18, 1 918. Serial No. 240,637.

such as strips of asbestos llike that used RESISTANCE ELEMENT.

ratentpa oct. 8,1918.

for thel core. This wrappinserves to press the coil into the -core and old the spires thereof spaced apart. The wrapping is then coated wlth a heat-transmitting insulating cement, such as that hereinafter describe' `and .the whole compressed in any suitable way to roduce a compacted resistance element ofp uniform diameter and character. An element of this construction ma be manufactured in continuous lengths an then cut into sections of the desired size for the individual units.

In Fig'. 2 I. have shown such a section cut to the desired length and Afolded back u on itself at 13, the thus folded length `being rther folded at 14' to aord a four-strand unit. The bared ends 15 and 16 of the resistance wire afford terminals which ma be connectedto the ends of the lead-wires not shown).

After the section has been'bent to the form shown in'-Fig. 2, producing the several strands, brass ferrules 17, 18, and 19 are slipped thereover, one at each end 'of `the un1t and one in the middle, which .serve not 80 only to keep the strands in position and thus form them into a unit, but to form radiating conductors which aid in transmitt the heat of the unit to the tool casing. ese

ferrules are held in position in any suitable way, preferably by cement 20.

The unit thus formed is baked at 'a temperature suiciently high to remove not only all moisture which may be present in the Acement or in theasbestos, but also any combustible material, such` as cotton or other textile fibers, which areordinaril aociated with the asbestos. This is-high y desirable o since the presence of the cotton in the nished unit renders the latter objectionable if placed in the utensil without prior baking, byy reason ofthe fact'that the heat of the resistance wires, when the 'utensil is in use, 4scorches the cotton and causes the latter to give of an odor, which is not only unpleas- 100 ant but a source of alarm to the user. After the unit has been completely dried and de- `odorized, it is ready for use, andthe leadwires may be connected to the terminals 15 and 16 of thezesistance.

In the modified construction shov'c'nA inFig.

Ihavesubstituted for' the insulating wrapping 12 an outer casing of insulating cement 'I of water lass. 5 wlilcli may 5e applied by dipping and is then pressed in and evenly distributed over the surface by any suitable means. This may be satisfactorily accomplished by hand,

or by drawing through a pliable die or by rolling.

Instead of a cement of the type just described I may use a thin aste or binder of silicafbpulverized micaa mixture thereo an this silica-cement may e orced into the interior of the resistance element by rolling the latter between plates having a definite minimum Ispacing to impart a uniform diameter to the product. After baking, the surface is rather hard and looks somewhat like enamel or glaze, but is nevertheless sufiiciently flexible.

A unit of the present type has not only the advantage of being readily and economically made, but it possesses the important characteristic that it will withstand, without injury, shocks such as it would receive when the utensil in which it is inserted is dropped on the floor or thrown on the dressing table as is frequently the case with hair curlers, heated combs, etc. In this respect it is much superior to resistance elements wound on rigid porcelain or lava cores which frequently break in use. Moreover, it is exible and can be bent, if necessary, during its introduction linto the tool, or 1t may occupy a curved position in the tool.

Various modifications will readily occur to those skilled in the art which do not depart from what I claim as my invention.

I claim: A

1. A resistance element of the type described comprising a core of soft insulating material, a coil 'of resistance wire wound thereon, a covering of 'insulating material pressed on said coil and serving, with the soft core, to maintain the spires of said coil spaced apart, a length thus formed being bent back upon itself to form a plurality of strands, means for holding said strands together at spaced intervals to form a unit, said unit being baked to remove contained moisture and combustible material, and being flexible.

2. A resistance element of the type described comprising a core of soft insulating material, a coil of resistance wire wound thereon, a covering of insulating material pressed on said coil and serving, with the soft core, to maintain the spires of said coil spaced apart, a length thus formed bein bent back upon itself to aord a plurality of strands, spaced metallic ferrules incasing said strands to form a unit and assist in the radiation of the heat of the coil, said unit being baked to remove contained moisture ald combustible material, and being iexi- 3. A resistance element of the type described 'comprising a core of soft insulating material, a coil of resistance wire wound' thereon, a covering of insulating material pressed on said coil and serving, with the soft core, to-maintain the spires 0f said coil spaced apart, said covering comprising a plastic mixture of alundum, powdered asbestos, and alkali silicate, said unit being baked to remove contained moisture and combustible material, and being exible.

In testimony whereof I have signed my name to this specification.

EDWARD SCHWARTZ.

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